A Lifesaving Transplant for Coral Reefs

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A mountainous star coral colony that was grown from an inch-square fragment cut a year earlier off of a parent colony.CreditCreditRichard Morin

By Richard Morin

Nov. 23, 2014

SUMMERLAND KEY, Fla. — David Vaughan plunges his right arm down to his elbow into one of nine elevated tanks where thousands of tiny colonies of coral are growing at an astonishing rate in shaded seclusion next to the Mote Tropical Research Laboratory.

“Now this is the exciting part. You ready for this?” he asks, straining to be heard over the relentless hiss of filtered saltwater squirting from a maze of pipes and plastic tubing into the shallow fiberglass tank, the size of a dining-room table.

Dr. Vaughan, a marine biologist who is executive director of the laboratory, retrieves a flat rock from the bottom. A chocolate-brown colony of brain coral, nearly eight inches wide, has grown on the stony surface, its distinctive fleshy, serpentine folds nearly covering the rock.

A year ago the colony began as inch-and-a-half-wide coral fragments cut with a band saw from the same parent colony. As if doused with a growth elixir, these coral “seeds” began to grow 25 times as fast as they would in the wild.

And when arranged a few inches apart on the rock, the mini-colonies quickly advanced across the surface and fused to become a single grapefruit-sized organism that continues to grow.

Other species grown from tiny coral seeds in the Mote lab have developed even faster — up to 50 times their normal rate.

Dr. Vaughan and a staff biologist, Christopher Page, say this quick-grow technique, called microfragmenting, may make it possible to mass-produce reef-building corals for transplanting onto dead or dying reefs that took centuries to develop — perhaps slowing or even reversing the alarming loss of corals in the Florida Keys and elsewhere.

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Divers "plant" live coral fragments that were grown in a nursery onto dead coral skeletons in the Florida keys using epoxy putty.CreditErich Bartels/Mote Marine Lab

“This is real,” Dr. Vaughan said. “This potentially can be a fix.”

Other scientists are excited, too. While there are other efforts around the world to grow new coral, “this is easily the most promising restoration project that I am aware of,” said Billy Causey, a coral expert who oversees all federal marine sanctuaries in the Southeastern United States, the Gulf of Mexico and the Caribbean for the National Oceanic and Atmospheric Administration.

“Dave and Chris are buying us time,” he added. “This will keep corals out there” until “we can come to understand what is happening to coral on the larger scale.”

Still, even Dr. Vaughan’s cheery optimism has its limits. A quarter of the earth’s corals have disappeared in recent decades, and the Mote scientists say no one can predict what will happen if the oceans continue to warm, pollution and acidification increase, overfishing further decimates species beneficial to coral, and land runoff continues to reduce the amount of life-giving sunlight that reaches the bottom.

“We do not know if this is a fix-all,” Mr. Page said. “At worst, we’re buying a little time. At best, we could restore the ecosystem.”

Living Rocks

On a breezy, sun-washed day, Dr. Vaughan, 61, welcomed a visitor to the Mote laboratory here, about 25 miles up the road from Key West.

He wore the uniform of the Keys — shorts, flip-flop sandals and a billowy white shirt. His shoulder-length hair, sun-bleached beard and weathered face speak of a lifetime working in the sun and saltwater.

For the past three years, he and Mr. Page have focused on “massive” corals, the species that create most of the structure on a living reef. These corals have proved less susceptible than other species to the effects of rising ocean temperatures, pollution and changes in water chemistry.

But unlike fast-growing branching corals, massive species like brain, star, boulder and mounding corals naturally grow less than two inches a year — so slowly they are nicknamed “living rocks.”

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CreditThe New York Times

Scientists and marine aquaculturists are successfully growing staghorn and other branching corals in offshore nurseries for replanting in the wild. But until now, the slow growth rate of massive corals has stymied all efforts to produce these species in sufficient quantities for reef restoration.

The research facility over which Dr. Vaughan presides looks more like an oil refinery than a laboratory. A pump sucks up ancient seawater trapped in the porous limestone 80 feet below ground. The water is first treated in two 1,000-gallon fiberglass tanks to remove traces of ammonia, carbon dioxide and hydrogen sulfide. Then it flows through a maze of four-inch PVC pipes and into 30 outdoor 180-gallon fiberglass tanks, called raceways. A fine-mesh canopy over the tanks shades them from the subtropical sun.

In nine of these raceways, more than 7,000 brain, star, boulder and mounding corals grow in neat rows on different surfaces: cement pucks, specially manufactured ceramic wafers, or travertine tiles from the local Home Depot. Each had grown from a microfragment about the size of a pencil eraser.

The ‘Eureka Mistake’

Dr. Vaughan stumbled upon the microfragmenting idea eight years ago. He was transferring colonies of elkhorn coral between aquariums in his lab. He reached to the bottom of a tank to retrieve a colony growing on a two-inch concrete puck.

“Part of the coral had grown over the back side and had attached to the bottom of the aquarium,” he said. When he grabbed it, “it broke off and left two or three polyps behind. I thought I just killed those. But oh, well, I moved the puck over.”

A week later he happened to glance at the abandoned polyps — the individual hydra-shaped, genetically identical organisms that make up a coral colony — on the bottom of the aquarium. “I noticed that those one to three polyps were now five to seven polyps,” he said. “They not only had lived — they had grown and had doubled in size.”

It was, he said, “my eureka mistake.” He cut a few more polyps from the original colony and placed them on other pucks. “And they grew like crazy. The coral seems to want to repair itself quickly and grow back over its lost ground before something else takes its territory.”

But it wasn’t until Mr. Page was hired in 2011 that Dr. Vaughan first applied this insight to the large-scale production of massive corals.

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Regrowing Coral

Scientists in the Florida Keys are using corals’ innate healing abilities to try to repopulate lost areas.

Mr. Page, 29, had raised corals in an aquarium as a teenager in Buffalo. He knew that hobbyists and live-coral dealers routinely split growing colonies into pieces to sell or trade. “This was something that could be done,” he said. “I had done it as a hobbyist. It was a chance to apply what I had done on a much larger scale and actually accomplish something big.”

Three years later, he said, he can produce 1,000 microfragments just one centimeter square (one-sixth of a square inch) in four days. And with more space and adequate funding, he added, “the sky’s the limit.”

Will these coddled corals survive in the wild? Early tests have been encouraging. More than a year after they were transplanted to offshore test sites, 134 of 150 colonies grown from microfragments continue to flourish, Mr. Page said.

Last year he planted eight fragments of brain coral on 18 dead coral “heads” — colonies of genetically identical polyps — each about two feet wide.

“They’re doing well,” he said. “They’re sheeting over the entire structure really nicely. In a year or maybe two from now, you will see one continuous colony that would have taken 15 to 30 years to grow” in the wild.

And Dr. Vaughan said he planned to place 200 coral tiles on a dead 1,000-year-old coral head “the size of a Volkswagen” in hopes of restoring it in just a year.

“Sounds like science fiction, doesn’t it?” he said with a chuckle.

Creating a Coral Thicket

In June, Mote scientists won federal approval to begin their most ambitious project yet — to create a living coral thicket on the limestone skeleton of a dead reef half a mile off Big Pine Key, just east of Key West.

They have started planting 4,000 nursery-raised corals — symmetrical brain, boulder star, great star and massive starlet — on the 2.5-acre test site. Those species will join more than 1,000 staghorn coral raised in Mote’s offshore nursery by a team led by another staff scientist, Erich Bartels.

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David Vaughan with one of nine shallow 180-gallon salt water tanks, which contain colonies of massive corals grown from tiny coral fragments.CreditRichard Morin

The goal, Dr. Vaughan said, is to create “in a very short period of time a reef like the reefs we remember” from decades ago.

The project, among the largest coral restorations ever attempted, is the first large-scale effort in the Keys, and one of the few in the world, to restore massive corals in the wild, Dr. Vaughan said. It is partly supported by a $35,000 grant from the Field Museum of Natural History in Chicago.

By late October the Mote team had transplanted a total of 720 nursery corals to the offshore site in three separate plantings roughly a month apart.

The first planting, on July 25, was a disaster. Parrotfish found the nursery-raised corals particularly tasty. While some colonies were untouched, most “got chomped,” Mr. Page said.

The researchers adjusted their technique. Instead of transplanting corals directly from the nursery to the test site, they temporarily placed them under wire cages near their intended permanent homes.

“They are doing fantastic,” Mr. Page said. “Predation significantly decreased after they acclimatized to site conditions” and were then relocated to the test site — perhaps because of subtle shifts in the color of the colonies, changes in their internal chemistry or other factors. (Color matters, the scientists found. Predators seemed to pass up darker corals in favor of fluorescent green ones.)

Planting will continue indefinitely. The researchers want to identify the corals that fare best, and to determine the ideal length of time needed to acclimate each species to make them less attractive to hungry fish.

If successful, they plan to use their nursery-raised corals to restore other degraded reef sites throughout the Keys and train others to set up their own coral factories.

But as Mr. Page noted, time is running out. “This may be our last, best chance,” he said.